1. Field of the Invention
This invention relates to a circuit for controlling the switching of the power supply of a motor and its application to the variation of speed.
2. Discussion of the Background
Switching circuits for a motor are known, particularly for a direct current, brushless motor. An example of these switching circuits is constituted by U.S. Pat. No. 3,364,407, which describes a switching circuit for supplying a direct current, brushless motor, comprising a six-point output series winding. This switching circuit is controlled by Hall-effect sensors. Generally, this type of circuit comprises a certain number of semiconductors assuring the switching of the power and other semiconductors which assure the control of the switching elements. Moreover, these types of circuits comprise a certain number of resistive elements necessary for the good operation of the electronics, which gives rise to losses by Joule effect and a dissipation, in the form of heat, of the power supplied. Finally, in the example of embodiment proposed in this U.S. patent and in the prior art in general, there is no galvanic decoupling between the switching elements of the power and the elements which assure the control of the switching elements.